EPHRAIM -- Three kayakers who failed to arrive at Eagle Harbor in Ephraim on Thursday afternoon were rescued early Friday morning after drifting more than 15 hours on the chilly waters of Green Bay.

They were identified as Alison Alter, 43, of Austin, Texas; her 9-year-old son Zach Suri; and Thomas Alter, 9, a cousin from Highland Park, Ill., Door County Sheriff's Lt. Jeff Farley said. They were vacationing with at least three other people.

Two of the three kayakers were treated for mild hypothermia and released from Bay Area Medical Center in Marinette. All three were wearing life jackets, the U.S. Coast Guard said in a press release.

The kayakers left Nicolet Bay at Peninsula State Park headed to Eagle Harbor in nearby Ephraim at about 2:45 p.m. Thursday and were expected to arrive by 4 p.m. When they failed to appear, the kayak rental company called the Door County Sheriff's Department about 6:30 p.m., Chief Deputy Gary Behling said Thursday.

"Very pleased and very fortunate that they were found alive," Sheriff Terry Vogel said.

The Coast Guard was notified that the kayakers had been sighted at about 6:05 a.m. Friday, eight to 10 miles northeast of Chambers Island, First Class Petty Officer Tyler Goss said. That is roughly due west of the tip of the Door County peninsula.

A Royal Canadian Air Force Hercules C-130 search plane from Trenton, Ontario, spotted them "between Whaleback Shoal and Cedar River," Goss said. The Coast Guard hoisted them out of the water using a Dolphin rescue helicopter from Traverse City, Mich. The kayaks also are being recovered.

A U.S. Coast Guard Dolphin helicopter from Traverse City, Mich., prepares to rescue three kayakers from Whaleback Shoal in Green Bay early Friday morning. The Coast Guard, the Royal Canadian Air Force and several local agencies assisted in the search and rescue.(Photo: U.S. Coast Guard photo courtesy of Royal Canadian Air Force)

"When we were notified at 6:17 this morning … you should have heard the incident command, everyone was hooting and hollering in joy that they are still OK," Farley said.

Authorities' main concern was whether the people were in the kayaks.

"When we were told 'swimmer in the water (and) all parties accounted for,' beautiful," he said.

Winds of 14 knots (16 mph) were blamed for the incident.

"Basically they went out in these kayaks, (and when) they got out there, the wind was too strong," Farley said. They did not know the water, and when they tried to turn around, they were carried farther out onto Green Bay.

The kayakers could see the searchers looking for them throughout the night. Rescuers were a little south of where Alter and the boys were floating.

Had the group had a cellphone or some kind of light with them, they could have been found sooner, Farley said. Alter reportedly didn't take her cell phone because she didn't have a waterproof case for it.

"Thank goodness (Alter) ... had the foresight to tie the two kayaks together," he said. She tied the kayaks to one another when they began to drift apart.

"Fortunately, the missing individuals stayed close to their boat, which made it much easier for our air crew to spot them in the water," said Maj. Martin Zimmer, officer in charge of the Joint Rescue Coordination Centre in Ontario.

Staying with the kayaks helped Alter and boys make it through the night, Goss said.

"They were absolutely lucky to survive," he said. "Water temps are still a little cold. Definitely hypothermic temperatures."

The water temperature was around 68 degrees off Peninsula State Park, Farley said.

The following agencies also helped with the search: Ephraim Fire and Rescue; Gibraltar, Sister Bay/Liberty Grove, Baileys Harbor and Sturgeon Bay fire departments; Sturgeon Bay police; Wisconsin and Michigan Departments of Natural Resources; Door County EMS and Emergency Management departments; Door County Human Services and the American Red Cross. Several private citizens also helped, including commercial fisherman Jeff Weborg.